Magnetic multivibrator



Dec. 25, 1945'. CHQDORQW 2,391,546

MAGNETIC MULTIVIBRATOR Filed Aug. 28, 1945 Tic i.

INVENITOR MARVIN CHODOROW BY ATTORNEY Patented Dec. 25, 1945 UNITED STATES PATENT OFFICE Maguire Industries, Incorporated,

tion of New York a corpora- Application August as, 1943, Serial No. 500,353

9 Claims.

My invention relates to a multi-vibrator, and more particularly such an apparatus wherein a pair of thermionic tubes, as a pair of magnetron tubes, are caused to conduct alternately, each tube influencing the conducting of the other. The invention is closely related to my copending patent application Serial No. 499,719, filed August 23, 1943, for Self-pulsing circuit.

One object of the invention is the provision of an electrical apparatus without moving parts, wherein alternate opposite pulses will be 1310", duced automatically. A further object. is the provision of such an apparatus employing a pair of thermionic. tubes, each being influenced. or controlled by the other. Other objects and advantages of the invention will be apparent-from the present specificatiom Certainforms of theinvention are shown by way of illustration in the accompanying drawing, inwhich Figure 1 is a diagrammatic sketch of an apparatus embodying the invention, and

Figure 2 is a diagrammatic sketch of an apparatus illustrating a variant formof the inventiOn; Y I

An important feature of the invention is the inclusion in a circuit of two thermionic tubes, together with means for periodically increasing the voltage across one or both tubes, and means governed by the action of each tube for increasing the required conducting voltage or opposition to conducting of the other tube. Obviously the invention is not limited to the use of two tubes.-

In the embodiment of the invention illustrated in Figure 1, a circuit is provided in'whichare connected two magnetron tubes II and H -A source of E. M. F'. (indicated by and signs) is conveniently included in the circuit in for energizing it.

For simplicity, themagnetron tubes H and H. are shown without the usual glass envelopes. The magnetron tube H comprises a filament cathode l3, connected across the terminals of a battery l4 and. also connected at one end to the circuit III. The cathode i3 is surrounded by a cylindrical anode 15, which is connected to the circuit l0. A condenser I2 is provided for building up the voltage across the magnetron tube H; and as here shown the condenser is connected in the circuit in parallel with the tube l I. The magnetron tube ll comprises a similar cathode Ili connectedacross the terminals of a battery M and also connected at one end to the circuit H). A similar cylindrical anode lfi surrounds the cathode Hi and is connected to the circuit IS. A

condenser ll is provided for building up the voltage across the magnetron tube H and in the present instance is connected in the circuit in parallel with the tube H Thus if a positive voltage is applied by the circuit l0 across the tube: that is to say, between the filament cathode l3 or 13 and the cylindrical anode 15 or 15, the tube will conduct.

As is well known, conducting of a cathode-anode tube of this kind may be influenced by amagnetic field appropriately applied to the tube. the present embodiment a separate magnet it,

excited by a winding I! unrelated to the circuit I0, is associated with the tube ll forv influencing. conducting of thetube, and a Similar. magnet] 5e, excited by a winding ll unrelated to the circuit 10 is associated with the tube l I for influencing conducting of that .tube. In the present illustrae tive embodiment of the invention, each magnet is positioned with its field directionparallel to that of the corresponding cathode. Accordingly, each magnetic field will oppose conducting of the ,corresponding magnetron tube. The stronger the field of the separate magnet therefore, the higher will be the required conducting .voltage, or the voltage atwhich the corresponding magnetron tube will conduct.

In order that conducting of the tube ll mayinfluence conducting of the tube Il an electromagnet IS is disposed adjacent the tube I l with its winding [9 connected in series with theltube I i. In the present embodiment of the invention the electro-magnet 18 is coaxial with the magnetron tube l I and the-separate magnet 6 and its winding lfi is so directed that the field of the electro-magnet l8 augments that of the separate magnet 16*. It will therefore be apparent that when the electro-magnet 18 is energized the resulting magnetic field, augmenting the field of the separate magnet 16*, will provide increased opposition to conducting of the tube Il in consequence of which a higher voltage will be required to cause the tube ll to conduct. Since the winding l9 of the electro-magnet [3 is connected in series with the magnetron tube I I, conductingof the tube l I will increase the opposition to firing of the-tube H and if the tube He is conducting, discharge of the tube I I may extinguish it.

In similar manner, conducting of the tube II may influence conducting of the tube H. To this end an electro-magnet I8 is disposed adjacent the tube H with its winding l9 connected in series with the tube H As herevshown, the electro-magnet I8 is coaxial'with the magnetron tube II and the separate magnet I6 and its winding I9 is so directed that the field of the electromagnet I8 augments that of the separate ma net IB. Thus, it 'will be evident that when the electro-magnet I8 is energized the resulting magnetic field augmenting the field of the separate magnet I6, will provide increased opposition to conducting of the tube II, in consequence of which a higher voltage will be required to cause the tube II to conduct. The winding I9 of the electro-magnet I8 being connected in series with the magnetron tube II, conducting of the tube II a will increase the opposition to conducting of the tube II; and if the tube II is conducting, discharge of the tube II a may extinguish it;

Alternate conducting of the magnetron tubes II and II, each influenced by the other, will occur as follows: Assume that thetube II; is conducting. The electro-magnet I8 is thereby energized, and the combined fields of the separate magnet Iii and the electromagnet I8 will act to oppose conducting of the tube II". When the condenser I2 has built up sufiicient voltage across the tube II a to overcome this opposition to conducting, the tube II will conduct. the winding I9 of the electro-magnet I8 is energized, and the field of the latter magnet augments that of the separate magnet I6 in opposing conducting of the tube II, and this tube is quenched. When the tube II is uenched, no energy is supplied to the winding I 9 of the electro-n'iagnet I8, and its field drops to zero. This reduces the field across the tube II, and hence its opposition to conducting. The tube I I therefore continues to conduct as the condenser Ii discharges and. the voltage across the tube Il drops.

When. the condenser I2 has built up sufficient voltage across the tube I I to overcome opposition to conducting imposed upon it by the magnets I6 and I8, the tube II conducts. The magnet I8 is thereby energized and the tube I I' is quenched. Thereupon the magnet I8 is de-energized, its field drops to zero, the opposition to conducting of the tube I I is reduced, and the tube II continues to conduct.

The cycle is thus repeated.

' From the foregoing it will be apparent t at, it energy is supplied to the circuit ID, as by means of the source of E. M. F., and if one tube, as the tube II, is first caused to conduct, the

tubes II and II willthen conduct alternately and automatically as long as energy is supplied to the circuit.

Variable resistances 2t and 20 are interposed between the condenser I2 and [2* respectively and the corresponding magnetron tubes II and II. Another variable resistance 2| is included in the shunt in which the condenser I2 is connected; and a corresponding variable resistance 2I is included in the shunt in which the condenser I2 is connected. Finally, variable resistances 22 and 22 are interposed between the source of E. M. F. and the respective shunts containing the condensers I2 and I2. ing these variable resistances and by' suitable selection of the capacities of the condenser Ii.- and I 2 the frequency and duration of the pulses may be controlled.

A variable condenser 23 and a resistance 24 are connected in parallel in the circuit between the cathode I of the magnetron tube I I' and the shunt containing the condenser I2. A correspondin variable condenser 23 and a resistance 24 are connected in parallel between the Thereupon By suitably adjustcathode I5 of the magnetron tube I I and the shunt containing the condenser I2. Thus the condenser-resistance unit 23, 24 is connected in series with the tube I I, and the condenser-resistance unit 23 24 is connected in series with the tube Il Each variable condenser is so adjusted that it provides approximate series resonance in the circuit, so that the voltage drop across the winding of the electro-magnet with which it is in series (which leads the current) will not extinguish the corresponding tube before the field of the magnet is established.

Obvious variations in the circuit and the combinations of electrical units will, of course, su gest themselves to those skilled in the art.

For example, it is possible to control conducting of both tubes and timing of the pulses by proper unbalance of the circuit constants. In the embodiment on the invention disclosed in Figure 1, such unbalance will be between the circuit constants on one side of the source of E. M. F. and those on. the other. In this case conducting and quenching of one tube alone will control the timing and duration of the pulses. Such unbalance may cause the tube II, for instance, to conduct and be extinguished as a result of its-own circuit constants alone. Because of this condition, conducting and quenching of the tube II" will follow action of the tube II, and the only function of the circuit constants related to the tube I I is to maintain this tube in conducting or extinguished condition until that condition has been changed by further action of the tube II.

The two halves of the circuit may be made as unsymmetrical as desired to give a wide choice of pulses.

Still another possible variation is the addition of an alternating current excitation to each of the separate magnets I6 and I 6. Such additional excitation may be applied by separate windings (not shown) or may be superimposed on the direct current windings I1 and I1 respectively. Since the additional A. C. excitation causes the field to fluctuate with the timing of the IA. 0;, conducting of the apparatus may be synchronized with the A. C.-direct1y or in multiples or fractions of its timing.

The embodiment of the invention shown in Figure 2 illustrates a further variation. In this embodiment no resistance-capacity shunt is eminvention depend solely upon theeircuit constants of the tube I I. I

The forms of the invention here particularly described and illustrated are presented merely to indicate how the invention may be applied. Other forms, difiering in detail but not in principle from those here set forth, and coming within the proper scope of the appended claims, will readily suggest themselves'to those skilledin the art.

I claim:

1. A multi-vibrator comprising a circuit, two

magnetrontubes in said circuit, means for pert-:-v

odically increasing the voltage across one of said tubes, and electromagnetic means governed by the action of onetube for increasing the opposition to conducting of the other tube.

' 2. A multi-vibrator comprising a circuit, two magnetron tubes in said circuit, means for periodically increasing the voltage across one of said tubes, and electromagnetic means governed by the action of one tube for increasing and decreasing the opposition to conducting of the other tube.

3. A mu1ti-vibrator comprising a circuit, two magnetron tubes in said circuit, means for periodically increasing the voltage across each tube, and an electro-magnet excited by the action of each tube for increasing the opposition to conducting of the other tube.

4. A multi-vibrator comprising a circuit, two magnetron tubes in said circuit, means for increasing the voltage across each tube, and an electro-magnet excited by the action of each tube for increasing and decreasin the opposition to conducting of the other tube.

5. A multi-vibrator comprising a circuit, two magnetron tubes in said circuit, means for periodically increasing the voltage across one of said tubes, and an electro-magnet connected in series. with each tube and disposed adjacent the other tube for increasing the opposition to conducting of the other tube.

6. A multi-vibrator comprising a circuit, two thermionic tubes in said circuit, an electro-magnet connected in series with one of said tubes disposed adjacent the other of said tubes to influence 25 its conducting, a second electro-magnet connected in series with the other of said tubes disposed adjacent said first-named tube to influence its conducting, and a condenser in circuit with one of.

each of said tubes for discharging through said tube to cause it to conduct.

8. A multi-vibrator comprising a circuit, two magnetron tubes in said circuit, an electro-magnet connected in series with one of said tubes disposed adjacent the other of said tubes to influence its conducting, a second electro-magnet connected in series withthe other of said tubes disposed adjacent said first-named tube to influence it conducting, and a condenser connected in parallel with one of said tubes for discharging through said tube to cause it to conduct.

9. A multi-vibrator comprising a circuit, two

' magnetron tubes in said circuit, an electro-magnot connected in series with one of said tubes disposed adjacent the other of said tubes to influence its conducting, a second electro-magnet connected in series with the other of said tubes disposed adjacent said first named tube to influence its conducting, and a separate condenser connected in parallel with each tube for discharging through said tubes for discharging through said tube to 30 said tube to cause it to conduct.

cause it to conduct.

MARVIN CHODOROW. 

